Oocyte and embryo handling apparatus

ABSTRACT

Oocyte extraction apparatus or embryo replacement apparatus has a flexible tube along which the oocyte or embryo passes. The tube extends along an outer jacket which maintains the temperature within the tube. The jacket may be thermally insulating or it may be heated such as with warmed liquid.

BACKGROUND OF THE INVENTION

This invention relates to oocyte and embryo handling apparatus.

Conventionally, an oocyte is extracted from a follicle using a needle towhich suction is applied so that the oocyte is aspirated into a testtube or other receptacle. Often a flushing liquid is supplied along asecondary lumen of the needle to assist removal. Once the oocyte hasbeen extracted, it is transferred to a suitable receptacle.

One problem with the apparatus used in this technique is that thetemperature of the liquid used to help flush out the oocytes from thepatient can fall below the ideal level, especially if the procedure isdelayed. Also, the temperature of the oocyte can fall appreciably duringits passage along the needle, its associated tubing and into the testtube. Similar problems exist when handling embryos.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide alternativeapparatus for use in handling an oocyte or embryo.

According to one aspect of the present invention there is providedapparatus for use in handling an oocyte or embryo including a tubeadapted for use in the handling of the oocyte or embryo and an elongatejacket extending along the tube, the jacket being arranged to maintainthe temperature within the tube.

The jacket is preferably flexible and may be thermally insulating, suchas of a foamed plastics. Alternatively, the jacket may be heated, suchas by a warmed fluid. The jacket may include a central bore in which thetube is received and two outer channels along which the warmed fluid issupplied. The outer channels may be of C shape. The jacket preferablyhas an inlet and outlet for flow of the fluid into and out of thejacket, the inlet and outlet being located at the same end of thejacket. The jacket may be extruded. The tube may be adapted for flow offlushing liquid along it. The apparatus may include a syringe connectedwith the tube and containing a flushing liquid for supply to the tube,the jacket extending along a part at least of the length of the syringe.Alternatively, the tube may be adapted for passage of an oocyte orembryo. Where the tube is adapted for passage of an oocyte the apparatusincluding collecting means connected with the tube for collecting theoocyte, and the jacket extending along a part at least of the length ofthe collecting means. The apparatus may include a dual-lumen oocyterecovery needle, the tube being connected to a flushing lumen of theneedle, an aspiration tube being connected with the second lumen of theneedle, and a second elongate jacket extending along the aspiration tubeto maintain the temperature of an oocyte flowing along the aspirationtube.

According to another aspect of the present invention there is provided amethod of oocyte recovery including the steps of connecting a tube to anoocyte recovery needle, warming the tube along a part at least of itslength, applying suction to the tube to draw an oocyte into the tube andcollecting the oocyte after passage through the warmed length of tube.

According to a third aspect of the present invention there is provided amethod of oocyte recovery including the steps of connecting anaspiration tube and a flushing tube to an oocyte recovery needle,maintaining the warmth of the tubes along a part at least of its length,applying flushing fluid via the flushing tube to the needle, applyingsuction to the aspiration tube to draw an oocyte into the aspirationtube and collecting the oocyte after passage through the aspirationtube.

Apparatus according to the present invention will now be described, byway of example, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of the apparatus;

FIG. 2 is a partly cut-away perspective view of a syringe for flushingliquid;

FIG. 3 is a partly cut-away view of a part of a modified form of theapparatus; and

FIG. 4 is a perspective view of alternative apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference first to FIG. 1 the apparatus includes a conventionaldual-lumen oocyte recovery needle 1 having a forward, patient end tip 2and a rear end hub 3. The two lumens within the needle are respectivelyfor supplying flushing liquid and for passage in the opposite directionof aspirated materials including oocytes and follicle fluid. Theflushing and aspiration lumens in the needle connect with respectiveports 4 and 5 on the hub 3. Attached with the flush and suction ports 4and 5 are respective tubes 6 and 7. The flushing tube 6 is terminated bya connector 8. The aspiration tube 7 extends through a bung 9 fittedinto the neck of a test tube 40. A second tube 41 extends through thebung 9 into the test tube 40 at one end and is connected at its otherend with a vacuum pump 42.

The apparatus further includes a syringe 11 connected to the flushingtube 6 and containing a suitable flushing fluid warmed to bodytemperature of about 37° C.

The apparatus is completed by two thermally-insulating jackets 20 and 30made of a thermally-insulating, flexible material such as a foamedplastics. The jacket 20 has a relatively narrow portion 21 along themajor part of its length, which encloses the entire length of the tube 6as a loose fit and has an enlarged rear end 22 enclosing the barrel ofthe syringe 11 as a close sliding fit. The other jacket 30 extends alongthe aspiration tube 7 from the hub 3 to the bung 9. The jacket 30terminates at the bung 9 although, in an alternative arrangement shownin FIG. 3, it could have an enlarged portion 31 at its rear end thatfits over the bung 9 and test tube 40.

In operation, the syringe 11 is filled with a flushing liquid previouslywarmed to body temperature. The nose of the syringe 11 is fitted ontothe connector 8 at the end of the flush tube 6 and the enlarged region22 of the jacket 20 is slid rearwardly to cover the barrel of thesyringe. The needle 1 is then used in the usual way to remove oocytesfrom the patient, turning on the vacuum pump 42 to suck oocytes into thetest tube 40, which would normally be in a warmed holder.

The insulating jackets of the present invention help maintain thetemperature of the flushing liquid before use and of the oocyte afterremoval from the patient. The insulating jackets are low cost so theycan be disposed of after a single use.

Although the insulating jackets described above are removable from thesyringe and tubes and can be used with conventional oocyte recoverysets, they could, instead, be fixed with the syringe or tube. Thejackets could be moulded about the apparatus.

The jackets described above maintain the temperature of the syringe andtubes by being thermally insulating. They could, however, maintain thetemperature in other ways. For example, the jackets could contain avolume of a previously heated substance such as a wax or gel thatmaintains the desired temperature by changing from a liquid to a solidat around body temperature. Alternatively, the jackets could include anelectrical heating element, which could be powered by an internalbattery or a remote power source.

FIG. 4 illustrates apparatus having a jacket heated by warmed fluidcirculated through the jacket.

The apparatus shown in FIG. 4 has a conventional oocyte recovery tube orcatheter 100 connected at its forward end 102 to a conventional oocyterecovery needle 103. At its rear end 104, the tube 100 is connected to acollection test tube 105 to which suction is applied so that therecovered oocytes are collected in the tube, in the usual way.

The apparatus has warming arrangement 110 comprising anelectrically-heated fluid warmer 111, such as of the kind sold under thetrade mark HOTLINE (a Registered Trade Mark of Level 1, Inc) by Level 1,Inc of Rockland, Mass., USA. The fluid warmer 111 provides arecirculating flow of water warmed to about 39° C. The warmer 111 isconnected by a dual-bore tubing 112 to a heat exchanger 113. The tubing112 has two bores 114 and 115, one for the warmed water flowing awayfrom the warmer 111 and the other for the returned water flowing back tothe warmer for reheating.

The heat exchanger 113 is preferably a modified version of that usedwith the HOTLINE warmer for warming infusion fluid supplied to apatient. The heat exchanger 113 is described in detail in U.S. Pat. No.5,063,994 and in U.S. Pat. No. 5,097,898. The heat exchanger 113 isextruded from a plastics material to form a flexible, elongate, tubularjacket of circular external section. The exchanger 113 has three boresextending in parallel along the length of the exchanger. A central bore116 is provided by a tubular portion 106 of circular section supportedby two radially-extending webs 117 and 118. The webs 117 and 118 bisectan outer concentric passage around the central bore 116 into two outerchannels 119 and 120 each having a C shape section. The central bore 116opens axially at the rear end 121 of the exchanger 113 through as an endcap 122. The outer channels 119 and 120 communicate via the cap 122 withrespective ones of the bores 114 and 115 of the tubing 112 and hencecommunicate with the fluid warmer 111. The forward end 123 of theexchanger 113 similarly has an end cap 124 within which the two outerchannels 119 and 120 communicate with one another so that water suppliedforwardly along one channel can flow back rearwardly along the otherchannel. The central bore 116 opens axially through the forward end cap124.

The oocyte recovery tube 100 extends through the central bore 116 of theheat exchanger 113 as a close sliding fit to ensure that there is a goodthermal contact between the tube and the tubular portion 106, therebypromoting efficient heat transfer to the tube. The bore 116 or tube 100may be coated with a lubricant such as a gel to ease insertion of thetube in the bore and to improve thermal contact. The heat exchanger 113extends along most of the length of the recovery tube 100 apart from ashort section 125 at its forward end, which is exposed to facilitatemanipulation, although the flexible nature of the heat exchanger doesallow the remainder of the tube to be easily manoeuvred.

In an alternative arrangement, the recovery tube would not project fromthe heat exchanger and, instead, the hub of the needle would be combinedwith the end cap of the heat exchanger. Such an arrangement has theadvantage of enabling the entire length of the oocyte recovery tubing tobe warmed. In order to ensure that the needle could still be manipulatedfreely it would be preferable for the material of the heat exchanger tobe selected for maximum flexibility.

In use, the fluid warmer 111 supplies warmed water at about bodytemperature to the rear end 121 of the exchanger 113, which flowsforwardly along one channel 119 and then rearwardly along the otherchannel 120. This ensures that the oocyte recovery tube 100 ismaintained very close to body temperature so as to maintain therecovered oocytes close to their ideal temperature during recovery.

Although alternative forms of heat exchanger could be used, thearrangement described, where fluid is supplied to and returned from theexchanger at its rear end, has several advantages. First, it keeps theforward end of the exchanger free of any additional tubing so that thesurgical site is kept uncluttered and so that there is less impedimentto manipulation of the forward end of the tube and exchanger. Second,the drop in temperature of the heated water flowing forwardly along thelength of the exchanger is in the opposite sense to that of the waterflowing rearwardly. This has the effect of reducing the overalltemperature gradient along the length of the exchanger, which minimizesthe thermal shock to which the oocytes are exposed.

The oocyte recovery tube could be inserted in the heat exchanger by theuser and removed after use so that the heat exchanger can be reused.There is no risk of contamination because there is no direct contactwith the heat exchanger itself.

The invention is not confined to oocyte recovery apparatus but couldalso be used in apparatus for use in handling embryos.

1. Oocyte recovery apparatus comprising a source of warming fluid, anoocyte recovery needle and a flexible tubular assembly connected at itsrear end with said source and at its forward end with said needle, saidtubular assembly including: a tubular passage along which an oocyteflows rearwardly of the assembly; an outer jacket surrounding saidtubular passage along which warming fluid flows from said source to theforward end of the assembly to warm said tubular passage; a return pathby which said warming fluid flows from the forward end of the assemblyto the source; a reservoir for receiving said cocyte; and an outlet ofsaid tubular passage to said reservoir, said outlet being locatedbetween the ends of the assembly such that said oocyte is warmed byfluid in said jacket during its passage from said needle to saidreservoir.
 2. Apparatus according to claim 1, wherein said outer jacketincludes C-shaped channels.
 3. A method of oocyte recovery comprisingthe steps of: connecting a tube to an oocyte recovery needle; warmingsaid tube along a part at least of its length; applying suction to saidtube to draw an oocyte into said tube; and collecting the oocyte afterpassage through the warmed length of said tube.
 4. A method of oocyterecovery comprising the steps of: connecting an aspiration tube and aflushing tube to an oocyte recovery needle; maintaining warmth of saidtubes along a part at least of their length; applying flushing fluid viasaid flushing tube to said needle; applying suction to said aspirationtube to draw an oocyte into said aspiration tube; and collecting theoocyte after passage through said aspiration tube.
 5. Apparatus for usein extracting an oocyte comprising: a dual-lumen oocyte recovery needlehaving a flushing lumen and an aspiration lumen; a reservoir forreceiving the oocyte; a connection between the reservoir and theaspiration lumen; a source of suction; a connection between the sourceof suction and the reservoir so that suction can be applied to draw anoocyte into the reservoir; a flushing tube connected with said flushinglumen; an aspiration tube connected with said aspiration lumen; a firstinsulating jacket extending along said flushing tube to maintain thetemperature of flushing liquid in said flushing tube; and a secondinsulating jacket extending along said aspiration tube to maintain thetemperature of an oocyte flowing along said aspiration tube. 6.Apparatus according to claim 5 including a syringe containing flushingliquid connected with said flushing tube, and wherein said firstinsulating jacket extends along a part at least of the length of saidsyringe.
 7. Apparatus according to claim 6 including a tube forcollecting an oocyte connected with said aspiration tube, and whereinsaid second insulating jacket extends along a part at least of thelength of said collecting tube.
 8. Apparatus according to claim 5,including a source of flushing fluid and a connection by which saidflushing fluid flows along said flushing tube.
 9. Apparatus according toclaim 8, wherein said source of flushing fluid includes a syringeconnected with said tube and containing said flushing liquid, andwherein said first insulating jacket extends along at least a part ofthe length of said syringe.
 10. Apparatus for use in extracting anoocyte comprising: an oocyte recovery needle; a flexible tube connectedwith said needle; a reservoir for receiving the oocyte; a connectionbetween the reservoir and the flexible tube; a source of suction; aconnection between the source of suction and the reservoir so thatsuction can be applied to draw an oocyte into the reservoir; a warmingjacket surrounding said flexible tube; and a supply of warmed liquidconnected with said jacket to warm said jacket and thereby warm saidflexible tube so as to maintain the temperature of an oocyte flowingalong said tube.
 11. Apparatus according to claim 10, wherein saidjacket is extruded.